The present invention relates to a fuel rail for fuel injected internal combustion engines.
Fuel injection systems for internal combustion engines commonly include a plurality of fuel injectors, each of which delivers fuel to an inlet port of the engine combustion chamber. Also, direct injection systems include fuel injectors that injection fuel directly into the combustion chamber of the engine. Such fuel injection systems often include a fuel rail having an elongated fuel passageway that distributes fuel to the fuel injectors through a plurality of fuel injector sockets that connect to the fuel injectors.
One type of fuel injection system includes a fuel pump that supplies pressurized fuel to the fuel rail from the fuel tank, and a fuel pressure regulator maintains the proper pressure within the fuel rail and meters excess fuel that is returned to the fuel tank by a return line. Alternately, returnless fuel systems have been developed that do not require a fuel return.
Existing fuel rails may be made of metal, such as stainless steel, having a relatively high weight, thus adding to the total weight of the vehicle with a resultant reduction in fuel economy. Further, metals have a relatively high thermal conductivity, which tends to cause the fuel to become heated. Finally, metal fuel rails may be relatively expensive to produce.
One aspect of the present invention is a composite fuel rail for delivering fuel to the fuel injectors of an internal combustion engine. The fuel rail includes an elongate body having a plurality of axially spaced transversely extending fuel injector sockets. The elongate body also includes an elongate, axially extending fuel passage intersecting the sockets to supply fuel to the sockets. The elongate body has an elongate polymer inner liner made of a chemically inert material that does not degrade substantially when exposed to fuel. The elongate body further includes a fiber reinforced outer shell extending over and covering the inner liner.
Another aspect of the present invention is a fuel rail for delivering fuel to the fuel injectors of an internal combustion engine. The fuel rail includes an elongate body having a plurality of axially spaced fuel injector sockets and an axially extending fuel passage intersecting the sockets to supply fuel to the sockets. The elongate body has an inner sleeve of liner made of a first fiber reinforced material. The elongate body also has an outer shell made of a second fiber reinforced material enveloping the inner liner.
Yet another aspect of the present invention is a method of fabricating a composite fuel rail, including providing a first mold cavity having a shape capable of producing an inner liner of a fuel rail. A second mold cavity is provided, the second mold cavity having a shape capable of producing an outer shell over an inner liner produced by the first mold cavity. A first polymer material is injected into the first mold cavity to form an inner liner having an elongate fuel passageway and a plurality of axially spaced fuel injector ports adapted to provide fuel to fuel injectors. The inner liner is positioned in the second mold cavity, and a second polymer material is injected into the second mold cavity to form an outer shell over the inner liner.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.